Recently, I encountered a unexpected problem when used the operation amplifier AD8397.Before described the problem, please see the attach file that is circuit schematic.
the range of the output is 0-10V(4*Vin)
When the Vin was less than 0.25V, the output was always low, and not equaled to 4*Vin. That means the output can not reach to less than 1V.
As soon as the negative power(Pin.4 of AD8397) changed to -3V or used another IC(TI: LM7322), the output can be able to reach to less than 1V. the circuit can achieve design requirement(output:0-10V).
My problem is that,
1, the negative power is GND, and why output cannot reach to less than 1V. From the datasheet, the output of swing is -11.83V at the condition of negative power -12V.I think that the output is about 0.2V at the condition of GND. so the output was 0.2-10V, but the actual result is 1-10V.
2,Anyway, as I described that, Can ADI engineer point out how the problem is or give some comments？